of these materials is so reliable that its use guarantees scald coated. In 

 years such as 1959-60, unusually hot weather during August and September may 

 markedly increase the susceptibility of some varieties to this disorder. 



The Available Materials 

 S TOP-SCALD (ethoxyquin ) 



This material should be used after harvest at the rate of 3 pints per 100 

 gallons of water (2700 ppm.)« It has a residue tolerance of 3 ppm. Preharvest 

 tree sprays are not advised because of the coinmon appearance of dark-spot , 

 res idue marks on the fruit and they may be considerably less effective than 

 post-harvest dips, sprays, or flooding applications. Also, Stop-Scald is 

 generally inferior to DPA for scald control on Cortland and Delicious. Stop 

 Scald's chief advantage over DPA is that it is not as apt to cause surface 

 injury to fruit that is box or bin flooded or dipped. This material has no 

 ripening action on stored fruit. Do not apply to fruit more than once. Allow 

 fruit to drain well after treatment. Keep the solution well agitated. A 100 

 gallon batch can be expected to treat about 1000 bushels of fruit. All fruit 

 treated after harvest must carry the label "Eth o >cyquin treated to retard spoilage ' 

 The letter ing mu st be as larg e a s other grade labels . 



D PA (diphenylam ine ) 



This material will be sold as a 55% and 837 formulation. Except for a few 

 varieties that are somewhat susceptible to DPA injury it should be applied at 

 the rate of 2000 ppm. (2 pounds of the 83% or 3 pounds of the 55% formulation). 

 Solutions for use on Rome Beauty and Baldwin should be reduced to 1000 ppm. (1 

 pound of the 83% or 1 1/2 pounds of the 55% formulation) to reduce the chances 

 of injury to the fruit. The residue tolerance is 10 ppm. This material is 

 generally m ore effective for sc ald control th an any other known chemical method 

 on most va rieties . 



a . Preharv est DPA Spra ys 



In Massachusetts tests dilute (IX) sprays have been nearly as effective as 

 post-harvest treatments. The fruit must be harvested within 36 hours following 

 treatment to be effective, however. Thorough coverage of the fruit surface must 

 be obtained. Do not apply sprays when temperatures are 80°? or higher. Do not 

 make repeat applications with DPA unless a heavy rain occurs between a tree 

 application aad harvest. Apply DPA separately as a dilute (IX) spray. 



b. Post-Harvest DPA Treatments 



Keep the suspension well agitated. A 100 gallon batch can be expected to 

 treat 1000 bushels of fruit. Excellent drainage of excess DPA suspensions is 

 necessary to avoid collection of liquid material around the fruit in the bottom 

 of containers when crate or bin-dipping, spraying or flooding is practiced. 

 Those who work with DPA should use rubber gloves and avoid inhaling the DPA 

 dust. DPA can be applied to fruit wraps and used for scald control by those 

 interested in wrapping each apple. This chemical has no apparent ripening action 

 on stored apples. A ll fruit treated after harvest must have a label on the 

 shipping container stating, "Tr eated with diphenylamine to retard spoilage" in 

 letters as large as the grade labels used on the package . 



